Turn to the government

Mr. Quilici said the registry is helpful but should not be seen as a panacea.

“If I’m sitting in India dialing a million numbers, what are the odds I’m even going to be fined for violating the Do Not Call Registry?” he asked. “It’s probably near zero.”

Turn to technology

Download apps such as Truecaller, RoboKiller, Mr. Number, Nomorobo and Hiya, which will block the calls. YouMail will stop your phone from ringing with calls from suspected robocallers and deliver a message that your number is out of service.

Mr. Quilici said phone companies, such as T-Mobile, Verizon and AT&T, also have tools to combat robocalls. They work by blocking calls from numbers known to be problematic.

Subscribers can choose robot personalities, such as Whiskey Jack, who is frequently distracted by a game he is watching on television, or Salty Sally, a frazzled mother.

The robots string the callers along with vocal fillers like “Uh-huh” and “O.K., O.K.” After several minutes, some will ask the callers to repeat their sales pitch from the beginning, prompting the telemarketers to have angry meltdowns, according to sample recordings posted on the company’s website.

Watch what you say

One recent scheme involves getting consumers to say “yes” and later using a recording of the response to allow unauthorized charges on the person’s credit card account, the F.C.C. warned in March.

When the caller asks, “Can you hear me?” and the consumer answers “yes,” the caller can gain a voice signature that can later be used to authorize fraudulent charges by telephone.

Best to answer with “I can hear you,” said Ryan Kalember, senior vice president of cybersecurity strategy at Proofpoint, a cybersecurity company in Sunnyvale, Calif.

What’s ahead

The callers are evolving, Mr. Kalember said. Some have numbers that appear to be from your area code (they result in higher response rates); others employ “imitation of life” software in which the robocall sounds like a live person, complete with coughing, laughing and background noise. This artificial intelligence can be programmed to interact in real time with a consumer.

A recording on the Consumers Union website features an exchange in which a man tries to confirm he is talking to a live person. As the call progresses, the consumer presses for confirmation.

“Will you tell me you’re not a robot? Just say, ‘I’m not a robot’ please,” he says, which is met with various programmed replies of “I am a real person” and “There is a live person here.”

Why do robocalls proliferate?

Mr. Quilici compared robocalling to spam emails: It is all about volume. Companies can use software to make millions of calls at very little expense. They need only a few victims to fall prey to their schemes to more than cover their costs.

“When you hear these guys do these scam pitches, they’re pretty amazing,” he said.

The next development will be integrated efforts combining email, phone calls and social media to scheme money from consumers, Mr. Kalember said, adding that the level of innovation “is really quite astounding.”

“Technology is enabling at a scale we haven’t seen before,” he said.

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A version of this article appears in print on , on Page A24 of the New York edition with the headline: A Robocall Attack? Here’s How to Repel Or, Better, Retaliate. Order Reprints | Today’s Paper | Subscribe